The invention relates generally to methods for manufacturing composites, and more particularly to a method for manufacturing a carbon nanotube composite.
Carbon nanotubes were discovered by Dr. Iijima at NEC Corporation, Japan in 1991. A carbon nanotube is a type of fullerene that exhibits more excellent thermal and mechanical properties than steel and other alloys, yet has low density characteristics similar to or below that of currently available ceramic or polymer composites. Typically, a carbon nanotube can have a heat conduction coefficient of 6600 W/mK (watts/milliKelvin) at room temperature, a tensile strength of up to 100 Gpa (gigapascal), and a Young's modulus of up to 1 Tpa (thousandpascal). Moreover, carbon nanotubes have outstanding chemical stability such as acid-alkali resistance, and resistance to oxidization below 600° C. The remarkable properties exhibited by carbon nanotubes has led scientists and engineers to devote much effort to developing mass production techniques. Over time, carbon nanotubes have become increasingly available, and more attention from both academia and industry is being focused on the applications of carbon nanotubes in bulk quantities. These applications include using carbon nanotubes as a filler material in a polymer matrix that serves as a reinforcement in structural materials.
However, carbon nanotube polymer composite is often difficult to produce when incorporated into a polymer matrix. Frequently, during the formation of such composite, gravity pulls and separates denser composite material from the lightweight carbon nanotube composite material. Moreover, due to their crystalline and electrical characteristics, carbon nanotubes tend to conglomerate into each other during the composite formation process rather than uniformly dispersing in the matrix composite material.
In order to solve the above-described problem, a method for manufacturing a carbon nanotube composite is provided. During the formation process of the composite, conglomerated carbon nanotubes are distributed by way of an ultrasonic cleaning process. Moreover, due to the dispersing effect achieved by the ultrasonic cleaning process, the carbon nanotubes are uniformly dispersed in a matrix composite material.
However, a composite obtained by the method contains carbon nanotubes that are disorderly distributed in a polymer matrix. The disorderly distribution of the carbon nanotubes adversely impairs physical and chemical properties of the carbon nanotubes. In addition, the performance of the carbon nanotube composite achieved by the method may be less satisfactory.
What is needed, therefore, is a method for manufacturing a composite having carbon nanotubes orderly arranged and uniformly dispersed therein.